I have made these a couple of times now and I will give two tips. One is to sprinkle a little fleur de sel over the top of the unbaked cookies, just after you have flattened them. That much chocolate needs a little salt. Also, they are easy to underbake. They will start to look crackly early but let them have the full 14 minutes in the oven – at least.

In a bwol, sift together the flour, cocoa, and baking powder. Stir in the salt and set aside. Place the chopped chocolat ein a heaproof bowl over a saucepan of very hot water (the bottom of the bowl should not touch the water), stirring occasionally until the chocolate is melted and smooth. Remove the bowl from the water and allow to cool for 5 to 10 minutes.

Combine the butter and sugar in the bowl of an electric mixer with the paddle attachment and cream on medium speed until well combined. Add the eggs, one at a time, mising on medium speed unti the eggs are incorporated.

Increase the speed to high and beat for a few minutes until the mixture is very light, creamy and pale in color, scraping the bowl down as needed. Add the melted chocolate and the vanilla extract and mix just until combined. Remove the bowl form the mixer and fold in the dry ingredients using a rubber spatula. Fold in the chocolate chips.

Start scooping the cookies as soon as you finish making the batter. The batter is very soft at first, but it starts firming up quickly as it sits, which will make it more difficult to portion. The easiest way to portion the cookies is with a 2-ounce ice cream scoop. Pack the scoop only about three-quarters full. Or use a scant 1/4 cup of cookie dough for each cookie.

Scoop the cookies onto parchment-lined baking sheets, placing them about 2 inches apart. Flatten each mount of dough slightly with your hand. (Tip: You can use a dampened hand, because the dough is sticky.)

Soon after the cookies are scooped, put them in the oven and bake them. If you are baking in batches, don’t refrigerate the scooped dough, but leave them at room temperature. These cookies will not spread properly if the dough is chilled first.

Bake the cookies until they are evenly cracked all over the tops and softly set, 14 to 16 minutes, rotating the pan about halfway through the baking time. If you have 2 pans of cookies in the oven at the same time, also switch them between racks.

Remove pans from the oven and cool on a wire rack. Allow the cookies to cool completely before removing them from the baking sheets with a metal spatula. They stick to the paper a bit, but you can scrape them off with a sturdy metal spatula easily enough.